The PS1 game is still a lot better in terms of fun but the PSP version wins in terms of style and sound.
You play as Sir Daniel Fortesque, an undead knight who has been risen from the grave to defeat the evil wizard Zarok and stop him from taking over the kingdom of Gallowmere.
Positives: This game is possibly the most charming and most artistic game I have ever played. The art style is brilliant and the characters really come to life thanks to this. The sound is also brilliant. The music sounds great (fully orchestrated and not synthetic sounding like the original). The voice overs are also brilliant and very well acted. Tom Baker (a Doctor Who actor and also voices Little Britain) lends his talent as the Grim Reaper. The humour is also brilliant. Probably one of the funniest games I have played, that isn't an adventure game made by LucasArts. The levels are designed better than they were in the original. The story is much more interesting as well.
Negatives: The controls are not easy as the were in the PS1 game and Sir Dan is not nearly as easy to move around as used to be. The graphics in technical terms are average and the framerate dips sometimes. It is a lot easier than the original in my opinion. Some of the weapons don't look nearly as good in the older version (the magic sword for instance. PS1: It is blue and spiky and looks nothing like the other swords. PSP: It looks a lot like the long sword except it has a bigger blade.). You can't use your sheild when you are holding a lot of weapons, the only ranged weapon you can use your sheild with is the worst one, the throwing daggers. In the PS1 you can use your sheild with all ranged weapons. This can be annoying as in one level you have to use a ranged weapon against enemies with guns and if you don't want to die you have to use your sheild and throwing daggers because you can't really dodge the bullets.
All in all, in terms of cosmetics (sound, art style, humour) this game exceeds in every category however the controls aren't nearly as good as they were and the graphics could be better.